Washington, D.C. 20549



Investment Company Act file number: (811- 05901)

Exact name of registrant as specified in charter: Putnam Investment Grade Municipal Trust

Address of principal executive offices: One Post Office Square, Boston, Massachusetts 02109

Name and address of agent for service:  Beth S. Mazor, Vice President 
  One Post Office Square 
  Boston, Massachusetts 02109 
Copy to:  John W. Gerstmayr, Esq. 
  Ropes & Gray LLP 
  One International Place 
  Boston, Massachusetts 02110 
Registrant’s telephone number, including area code:  (617) 292-1000 

Date of fiscal year end: November 30, 2006

Date of reporting period: February 28, 2006


Item 1. Schedule of Investments:

Putnam Investment Grade Municipal Trust       

The fund's portfolio       
2/28/06 (Unaudited)       
Key to abbreviations       
AMBAC -- AMBAC Indemnity Corporation       
COP -- Certificate of Participation       
FGIC -- Financial Guaranty Insurance Company       
FHA Insd. -- Federal Housing Administration Insured       
FHLMC Coll. -- Federal Home Loan Mortgage Corporation Collateralized       
FNMA Coll. -- Federal National Mortgage Association Collateralized       
FSA -- Financial Security Assurance       
GNMA Coll. -- Government National Mortgage Association Collateralized       
G.O. Bonds -- General Obligation Bonds       
MBIA -- MBIA Insurance Company       
PSFG -- Permanent School Fund Guaranteed       
U.S. Govt. Coll. -- U.S. Government Collateralized       
VRDN -- Variable Rate Demand Notes       
XLCA -- XL Capital Assurance       

MUNICIPAL BONDS AND NOTES (158.7%)(a)       

  Rating (RAT)  Principal amount  Value 
Alabama (0.2%)       
Sylacauga, Hlth. Care Auth. Rev. Bonds (Coosa Valley Med. Ctr.), Ser. A, 6s, 8/1/25  B/P  $400,000  $413,032 

Arizona (1.5%)       
AZ Hlth. Fac. Auth. Hosp. Syst. Rev. Bonds (John C. Lincoln Hlth. Network), 6 3/8s, 12/1/37 (Prerefunded)  BBB  500,000  581,105 
Casa Grande, Indl. Dev. Auth. Rev. Bonds (Casa Grande Regl. Med. Ctr.), Ser. A, 7 5/8s, 12/1/29  B+/P  1,175,000  1,305,378 
Pima Cnty., Indl Dev. Auth. Rev. Bonds (Horizon Cmnty. Learning Ctr.), 5.05s, 6/1/25  BBB-  525,000  510,479 
Scottsdale, Indl. Dev. Auth. Hosp. Rev. Bonds (Scottsdale Hlth. Care), 5.8s, 12/1/31 (Prerefunded)  A3  1,000,000  1,074,930 

Arkansas (2.1%)       
AR State Hosp. Dev. Fin. Auth. Rev. Bonds (Washington Regl. Med. Ctr.), 7 3/8s, 2/1/29 (Prerefunded)  Baa2  3,000,000  3,411,930 
Independence Cnty., Poll. Control Rev. Bonds (Entergy, Inc.), 5s, 1/1/21 (Prerefunded)  A-  500,000  507,540 
Little Rock G.O. Bonds (Cap. Impt.), FSA, 3.95s, 4/1/19  Aaa  895,000  885,576 

California (19.8%)       
Anaheim, Pub. Fin. Auth. Tax Alloc. Rev. Bonds, MBIA, 6.45s, 12/28/18  Aaa  4,000,000  4,285,520 
CA Hlth. Fac. Auth. Rev. Bonds (Sutter Hlth.), Ser. A, MBIA, 5 3/8s, 8/15/30  Aaa  2,500,000  2,608,650 
CA State G.O. Bonds       
5 1/8s, 4/1/23  A2  500,000  531,740 
5.1s, 2/1/34  A2  750,000  764,783 
CA State Dept. of Wtr. Resources Rev. Bonds, Ser. A       
6s, 5/1/15 (Prerefunded)  Aaa  1,500,000  1,716,450 
AMBAC, 5 1/2s, 5/1/13 (SEG)  Aaa  13,000,000  14,465,230 
5 1/2s, 5/1/11  A2  1,500,000  1,627,920 
CA State Econ. Recvy. G.O. Bonds, Ser. A, 5s, 7/1/16  Aa3  1,000,000  1,067,270 
CA Statewide Cmnty. Dev. Auth. COP (The Internext Group), 5 3/8s, 4/1/30 (Prerefunded)  BBB  1,750,000  1,767,325 
Cathedral City, Impt. Board Act of 1915 Special Assmt. Bonds (Cove Impt. Dist.), Ser. 04-02, 5.05s, 9/2/35       
(Prerefunded)  BB+/P  270,000  267,138 
Chula Vista Rev. Bonds (San Diego Gas), Ser. B, 5s, 12/1/27 (Prerefunded)  A1  640,000  661,811 
Gilroy, Rev. Bonds (Bonfante Gardens Park), 8s, 11/1/25 (Prerefunded)  D/P  576,000  475,471 
Golden State Tobacco Securitization Corp. Rev. Bonds       
Ser. 03 A-1, 6 1/4s, 6/1/33  BBB  1,000,000  1,095,440 
Ser. B, 5 5/8s, 6/1/38 (Prerefunded)  Aaa  1,500,000  1,676,880 
Ser. 03 A-1, 5s, 6/1/21  BBB  500,000  504,800 
Orange Cnty., Cmnty. Fac. Dist. Special Tax Rev. Bonds (No. 02-1 Ladera Ranch), Ser. A, 5.55s, 8/15/33  BBB/P  450,000  462,992 
Riverside Cnty., Redev. Agcy. Tax Alloc., Ser. A, XLCA, 5s, 10/1/29 (Prerefunded)  Aaa  4,700,000  4,909,761 
Roseville, Cmnty. Fac. Special Tax Bonds (Dist. No. 1 -Westpark), 5 1/4s, 9/1/19 (Prerefunded)  BB/P  875,000  898,695 
Sacramento, Special Tax Bonds (North Natomas Cmnty. Fac.), 5s, 9/1/18  BB/P  1,040,000  1,056,546 
Santa Clara Cnty., Fin. Auth. Lease Rev. Bonds (Multiple Fac.), Ser. I, AMBAC, 5s, 5/15/20  Aaa  3,000,000  3,236,040 
Vallejo, COP (Marine World Foundation), 7.2s, 2/1/26 (Prerefunded)  BBB-/P  1,400,000  1,459,920 

Colorado (4.5%)       
CO Hlth. Fac. Auth. Rev. Bonds (Hlth. Fac.-Evangelical Lutheran), 3.35s, 10/1/06  A3  2,500,000  2,485,550 
CO Springs, Hosp. Rev. Bonds       
6 3/8s, 12/15/30  A3  1,515,000  1,667,364 
6 3/8s, 12/15/30 (Prerefunded)  A3  1,485,000  1,675,615 
CO State Hsg. Fin. Auth. Rev. Bonds (Single Fam.)       
Ser. B-2 , 7s, 5/1/26  Aa2  125,000  125,423 
Ser. B-3, 6.8s, 11/1/28  Aa2  65,000  66,022 
Denver, City & Cnty. Arpt. Rev. Bonds, MBIA, 5 1/2s, 11/15/25 (Prerefunded)  Aaa  2,500,000  2,557,300 
U. of CO. Enterprise Syst. Rev. Bonds, FGIC, 5s, 6/1/26  Aaa  1,650,000  1,752,762 

Delaware (0.7%)       

GMAC Muni. Mtge. Trust 144A sub. notes       
Ser. A1-3, 5.3s, 10/31/39  A3  500,000  513,190 
Ser. A1-2, 4.9s, 10/31/39  A3  1,000,000  1,009,070 

District of Columbia (1.8%)       
DC G.O. Bonds, Ser. B, FSA, 5 1/4s, 6/1/26  Aaa  4,000,000  4,183,960 

Florida (3.0%)       
Escambia Cnty., Hlth. Fac. Auth. Rev. Bonds (Baptist Hosp. & Baptist Manor), 5 1/8s, 10/1/19  A3  1,895,000  1,939,419 
Lee Cnty., Indl. Dev. Auth. Rev. Bonds (Alliance Cmnty.), Ser. C, 5 1/2s, 11/15/29  BBB-  1,000,000  1,003,790 
Miami Beach, Hlth. Fac. Auth. Hosp. Rev. Bonds (Mount Sinai Med. Ctr.), 5 3/8s, 11/15/28  BB+  2,000,000  2,039,300 
Okeechobee Cnty., Solid Waste Mandatory Put Bonds (Waste Mgt./Landfill), Ser. A, 4.2s, 7/1/09  BBB  375,000  375,908 
Reunion West, Cmnty. Dev. Dist. Special Assmt. Bonds, 6 1/4s, 5/1/36  BB-/P  850,000  897,005 
Tern Bay, Cmnty. Dev. Dist. Rev. Bonds, Ser. B, 5s, 5/1/15  BB-/P  450,000  446,967 
Tolomato, Cmnty. Dev. Dist. Special Assmt., 5.4s, 5/1/37  BB-/P  175,000  176,622 

Georgia (5.4%)       
Atlanta, Arpt. Rev. Bonds, Ser. B, FGIC, 5 5/8s, 1/1/30  Aaa  1,500,000  1,581,015 
Atlanta, Wtr. & Waste Wtr. Rev. Bonds, Ser. A, FGIC, 5s, 11/1/38 (Prerefunded)  Aaa  1,045,000  1,102,768 
Burke Cnty., Poll. Control Dev. Auth. Mandatory Put Bonds (GA Power Co.), 4.45s, 12/1/08  A2  2,300,000  2,348,737 
Cobb Cnty., Dev. Auth. U. Fac. Rev. Bonds (Kennesaw State U. Hsg.), Ser. A, MBIA, 5s, 7/15/29  Aaa  5,215,000  5,502,764 
Med. Ctr. Hosp. Auth. Rev. Bonds, MBIA, 6.367s, 8/1/10  Aaa  600,000  601,008 
Rockdale Cnty., Dev. Auth. Solid Waste Disp. Rev. Bonds (Visay Paper, Inc.), 7.4s, 1/1/16 (Prerefunded)  B+/P  1,200,000  1,203,708 

Hawaii (0.4%)       
HI State Hsg. & Cmnty. Dev. Corp. Rev. Bonds (Single Fam. Mtge.), Ser. B, 3.7s, 1/1/22  Aaa  975,000  967,385 

Idaho (0.2%)       
ID Hsg. & Fin. Assn. Rev. Bonds (Single Fam. Mtge.), Ser. C-2, FHA Insd., 5.15s, 7/1/29  Aaa  500,000  509,910 

Illinois (10.4%)       
Chicago, G.O. Bonds, Ser. A, FSA, 5s, 1/1/27 (Prerefunded)  Aaa  4,270,000  4,472,398 
Chicago, Board of Ed. G.O. Bonds (School Reform), Ser. A       
AMBAC, 5 1/4s, 12/1/27 (Prerefunded)  Aaa  2,500,000  2,620,775 
FGIC, zero %, 12/1/18 (Prerefunded)  Aaa  5,440,000  3,151,338 
Cook Cnty., Cmnty. G.O. Bonds (Cons. School Dist. No. 64 Pk. Ridge), FSA, 5 1/2s, 12/1/16 (Prerefunded)  Aaa  1,580,000  1,801,548 
IL Dev. Fin. Auth. Rev. Bonds (Midwestern U.), Ser. B, 6s, 5/15/26  A-  1,600,000  1,752,336 
IL Dev. Fin. Auth. Hosp. Rev. Bonds (Adventist Hlth. Syst./Sunbelt Obligation), 5.65s, 11/15/24  A+  2,500,000  2,701,425 
IL U. Rev. Bonds (Auxiliary Fac. Syst.), Ser. A, AMBAC, 5 1/4s, 4/1/19 (Prerefunded)  Aaa  1,945,000  2,199,134 
Schaumburg, G.O. Bonds, Ser. B, FGIC, 5s, 12/1/27 (Prerefunded)  Aaa  5,000,000  5,260,000 

Indiana (2.2%)       
IN State Dev. Fin. Auth. Env. Impt. Rev. Bonds (USX Corp.), 5.6s, 12/1/32 (Prerefunded)  Baa1  2,600,000  2,696,564 
Purdue U. VRDN (Student Fee), Ser. T, 3.17s, 7/1/27  VMIG1  1,250,000  1,250,000 
Rockport, Poll. Control Rev. Bonds (Indiana-Michigan Pwr.), Ser. A, 4.9s, 6/1/25  Baa2  1,000,000  1,009,060 

Iowa (0.9%)       
IA Fin. Auth. Hlth. Care Fac. Rev. Bonds (Care Initiatives), 9 1/4s, 7/1/25  BBB-/P  1,695,000  2,032,678 

Louisiana (0.9%)       
Ernest N. Morial-New Orleans, Exhibit Hall Auth. Special Tax Bonds, Ser. A, AMBAC, 5 1/4s, 7/15/21  Aaa  1,500,000  1,586,175 
LA Pub. Fac. Auth. Rev. Bonds (Pennington Med. Foundation), 5s, 7/1/16  A3  400,000  424,536 

Maine (0.6%)       
ME State Hsg. Auth. Rev. Bonds, Ser. D-2-AMT, 5s, 11/15/27  Aa1  1,275,000  1,300,564 

Massachusetts (11.1%)       
MA State Dev. Fin. Agcy. Rev. Bonds (MA Biomedical Research), Ser. C, 6 3/8s, 8/1/17  A1  2,785,000  3,060,255 
MA State Hlth. & Edl. Fac. Auth. Rev. Bonds       
(Civic Investments), Ser. A, 9s, 12/15/15  BBB-/P  1,000,000  1,216,010 
(Jordan Hosp.), Ser. E, 6 3/4s, 10/1/33  BBB-  750,000  821,018 
(Med. Ctr. of Central MA), AMBAC, 6.55s, 6/23/22  Aaa  16,400,000  17,344,968 
(UMass Memorial), Ser. D, 5s, 7/1/33 (Prerefunded)  Baa2  500,000  502,185 
MA State Hsg. Fin. Agcy. Rev. Bonds (Rental Mtge.), Ser. C, AMBAC, 5 5/8s, 7/1/40 (Prerefunded)  Aaa  2,500,000  2,552,425 

Michigan (4.3%)       
Detroit, Swr. Disp. VRDN, Ser. B, FSA, 2.97s, 7/1/33 (Prerefunded)  VMIG1  3,500,000  3,500,000 
Dickinson Cnty., Econ. Dev. Corp. Poll. Control Rev. Bonds (Intl. Paper Co.), Ser. A, 4.8s, 11/1/18 (Prerefunded)  BBB  900,000  896,562 
Flint, Hosp. Bldg. Auth. Rev. Bonds (Hurley Med. Ctr.), 6s, 7/1/20  Baa3  75,000  78,147 
MI State Hosp. Fin. Auth. Rev. Bonds       
(Oakwood Hosp.), Ser. A, 5 3/4s, 4/1/32  A2  1,000,000  1,060,090 
(Holland Cmnty. Hosp.), Ser. A, FGIC, 5 3/4s, 1/1/21  A2  1,250,000  1,356,338 

MI State Hsg. Dev. Auth. Rev. Bonds, Ser. A, 3.9s, 6/1/30  Aaa  1,200,000  1,194,432 
MI State Strategic Fund, Ltd. Rev. Bonds (Detroit Edison Poll. Control), 5.65s, 9/1/29  A3  575,000  604,590 
Saginaw Cnty., G.O. Bonds (Healthsource Saginaw, Inc.), MBIA, 5s, 5/1/26  Aaa  1,210,000  1,287,658 

Minnesota (2.1%)       
Cohasset, Poll. Control Rev. Bonds (Allete, Inc.), 4.95s, 7/1/22 (Prerefunded)  A  2,500,000  2,544,225 
Minneapolis, Cmnty. Dev. Agcy. Supported Dev. Rev. Bonds, Ser. G-3, 5.45s, 12/1/31  A+  1,705,000  1,864,503 
St. Paul, Hsg. & Redev. Auth. Hosp. Rev. Bonds (Hlth. East), 6s, 11/15/25  Baa3  350,000  384,234 

Mississippi (2.4%)       
Lowndes Cnty., Solid Waste Disp. & Poll. Control Rev. Bonds (Weyerhaeuser Co.)       
Ser. A, 6.8s, 4/1/22  Baa2  500,000  605,455 
Ser. B, 6.7s, 4/1/22  Baa2  525,000  629,927 
MS Bus. Fin. Corp. Poll. Control Rev. Bonds (Syst. Energy Resources, Inc.), 5 7/8s, 4/1/22  BBB-  1,750,000  1,771,298 
MS Dev. Bk. Special Obligation Rev. Bonds (Jackson MS), FSA, 5 1/4s, 3/1/21 (Prerefunded)  Aaa  1,385,000  1,565,410 
MS Home Corp. Rev. Bonds (Single Fam. Mtge.), Ser. B-2, GNMA Coll., FNMA Coll., 6.45s, 12/1/33  Aaa  810,000  852,630 

Missouri (2.3%)       
Cape Girardeau Cnty., Indl. Dev. Auth. Hlth. Care Fac. Rev. Bonds (St. Francis Med. Ctr.), Ser. A, 5 1/2s, 6/1/16  A+  1,250,000  1,350,513 
MO Hsg. Dev. Comm. Rev. Bonds (Home Ownership), Ser. D, GNMA Coll., FNMA Coll., 5.55s, 9/1/34  Aaa  1,145,000  1,184,732 
MO State Hlth. & Edl. Fac. Auth. Rev. Bonds (BJC Hlth. Syst.), 5 1/4s, 5/15/32  Aa2  1,000,000  1,050,010 
MO State Hsg. Dev. Comm. Mtge. Rev. Bonds (Single Fam. Homeowner Loan)       
Ser. A-2, GNMA Coll., 6.3s, 3/1/30  AAA  885,000  910,116 
Ser. C, GNMA Coll., FNMA Coll., 5.6s, 9/1/35 (Prerefunded)  AAA  700,000  746,186 

Nevada (3.7%)       
Clark Cnty., Arpt. Rev. Bonds, Ser. A-2, FGIC, 5 1/8s, 7/1/26  Aaa  5,105,000  5,404,204 
Clark Cnty., Impt. Dist. Special Assmt. (Summerlin No. 151), 5s, 8/1/25  BB/P  700,000  704,977 
Henderson, Local Impt. Dist. Special Assmt. Bonds       
(No. T-16), 5.1s, 3/1/21 (Prerefunded)  BB-/P  1,000,000  1,008,660 
(No. T-17), 5s, 9/1/25 (Prerefunded)  BB-/P  225,000  224,444 
(No. T-14), 4 3/4s, 3/1/10  BB-/P  1,135,000  1,139,915 

New Hampshire (0.4%)       
NH State Bus. Fin. Auth. Poll. Control Rev. Bonds, 3 1/2s, 7/1/27  Baa2  950,000  924,198 

New Jersey (5.9%)       
NJ Econ. Dev. Auth. Rev. Bonds       
(Cedar Crest Vlg., Inc.), Ser. A, 7 1/4s, 11/15/31  BB-/P  650,000  705,400 
(Cigarette Tax), 5 3/4s, 6/15/29  Baa2  1,750,000  1,882,195 
(Motor Vehicle), Ser. A, MBIA, 5s, 7/1/27  Aaa  5,000,000  5,292,800 
NJ State G.O. Bonds, Ser. F, MBIA, 5 1/2s, 8/1/11  Aaa  3,100,000  3,390,346 
NJ State Edl. Fac. Auth. Rev. Bonds (Fairleigh Dickinson), Ser. C, 6s, 7/1/20  BBB-/F  750,000  813,803 
Tobacco Settlement Fin. Corp. Rev. Bonds       
6 3/4s, 6/1/39  BBB  500,000  559,020 
6s, 6/1/37  BBB  1,000,000  1,047,520 

New Mexico (0.5%)       
NM Fin. Auth. Rev. Bonds, Ser. A, MBIA, 5s, 6/15/22  Aaa  750,000  801,578 
NM Mtge. Fin. Auth. Rev. Bonds (Single Fam. Mtge.), Ser. D-2, GNMA Coll., FNMA Coll., FHLMC Coll., 5.64s, 9/1/33  AAA  440,000  457,666 

New York (19.7%)       
NY City, G.O. Bonds, Ser. B, 5 1/4s, 12/1/09  A1  7,780,000  8,200,353 
NY City, Hsg. Dev. Corp. Rev. Bonds, Ser. A, FGIC, 5s, 7/1/25  Aaa  500,000  528,600 
NY City, Indl. Dev. Agcy. Rev. Bonds       
(Liberty-7 World Trade Ctr.), Ser. A, 6 1/4s, 3/1/15  B-/P  500,000  526,345 
(Brooklyn Navy Yard Cogen. Partners), Ser. G, 5 3/4s, 10/1/36 (Prerefunded)  BBB-  2,000,000  2,008,660 
NY City, Indl. Dev. Agcy. Special Fac. Rev. Bonds (British Airways PLC), 5 1/4s, 12/1/32  Ba2  750,000  670,898 
NY City, Muni. Wtr. & Swr. Fin. Auth. Rev. Bonds       
Ser. B, 5 3/4s, 6/15/26 (Prerefunded)  AA+  4,100,000  4,263,221 
Ser. D, 5s, 6/15/37  AA+  7,500,000  7,862,775 
NY State Energy Research & Dev. Auth. Gas Fac. Rev. Bonds (Brooklyn Union Gas), 6.952s, 7/1/26  A+  2,000,000  2,060,160 
NY State Env. Fac. Corp. Rev. Bonds, 5s, 6/15/32  Aaa  4,000,000  4,203,880 
NY State Hwy. Auth. Rev. Bonds (Hwy. & Bridge Trust Fund), Ser. B, FGIC, 5s, 4/1/17  Aaa  3,000,000  3,264,060 
Port. Auth. NY & NJ Special Oblig. Rev. Bonds (JFK Intl. Air Term. - 6), MBIA, 5.9s, 12/1/17  Aaa  10,500,000  11,072,040 
Suffolk Cnty., Indl. Dev. Agcy. Rev. Bonds (Peconic Landing), Ser. A, 8s, 10/1/30  B+/P  650,000  716,183 

North Carolina (3.3%)       
NC Eastern Muni. Pwr. Agcy. Syst. Rev. Bonds       
Ser. D, 6 3/4s, 1/1/26  Baa2  1,000,000  1,106,730 
Ser. A, 5 3/4s, 1/1/26  Baa2  2,000,000  2,113,980 
NC State Muni. Pwr. Agcy. Rev. Bonds (No. 1, Catawba Elec.), Ser. B, 6 1/2s, 1/1/20  A3  3,500,000  3,869,040 

U. of NC Chapel Hill Hosp. Rev. Bonds, Ser. A, 5s, 2/1/11  AA-  500,000  526,405 

North Dakota (0.4%)       
ND State Board of Higher Ed. Rev. Bonds (U. of ND Hsg. & Auxillary Fac.), FSA       
5s, 4/1/21  Aaa  400,000  427,756 
5s, 4/1/19  Aaa  500,000  538,110 

Ohio (2.8%)       
Brookville, Local School Dist. G.O. Bonds, FSA, 5s, 12/1/31 (Prerefunded)  Aaa  1,000,000  1,049,660 
Coshocton Cnty., Env. Rev. Bonds (Smurfit-Stone Container Corp.), 5 1/8s, 8/1/13 (Prerefunded)  CCC+  600,000  569,616 
OH State Air Quality Dev. Auth. Rev. Bonds (Toledo Poll. Control), Ser. A, 6.1s, 8/1/27  Baa2  2,000,000  2,096,500 
Rickenbacker, Port Auth. Rev. Bonds (OASBO Expanded Asset Pooled), Ser. A, 5 3/8s, 1/1/32 (Prerefunded)  A2  2,500,000  2,794,975 

Oklahoma (0.5%)       
OK Dev. Fin. Auth. Rev. Bonds (Hillcrest Hlth. Care Syst.), Ser. A, U.S. Govt. Coll., 5 5/8s, 8/15/29 (Prerefunded)  Aaa  1,050,000  1,127,312 

Oregon (0.4%)       
OR State Hsg. & Cmnty. Svcs. Dept. Rev. Bonds (Single Family Mtge.), Ser. K, 5 5/8s, 7/1/29  Aa2  845,000  874,896 

Pennsylvania (5.4%)       
Bucks Cnty., Indl. Dev. Auth. Retirement Cmnty. Rev. Bonds (Ann's Choice, Inc.), Ser. A, 5.4s, 1/1/15 (Prerefunded)  BB/P  530,000  532,645 
Carbon Cnty., Indl. Dev. Auth. Rev. Bonds (Panther Creek Partners), 6.65s, 5/1/10  BBB-  1,005,000  1,062,235 
Lancaster Cnty., Hosp. Auth. Rev. Bonds (Gen. Hosp.), 5 1/2s, 3/15/26  A  1,500,000  1,587,060 
Lehigh Cnty., Gen. Purpose Auth. Rev. Bonds (Lehigh Valley Hosp. Hlth. Network), Ser. A, 5 1/4s, 7/1/32  A1  1,000,000  1,040,810 
PA State Econ. Dev. Fin. Auth. Resource Recvy. Rev. Bonds (Northampton Generating), Ser. A, 6.6s, 1/1/19  B+  750,000  749,205 
PA State Higher Edl. Fac. Auth. Rev. Bonds (Philadelphia College of Osteopathic Med.), 5s, 12/1/08  A  1,045,000  1,076,225 
Philadelphia, School Dist. G.O. Bonds, Ser. D, FGIC, 5s, 6/1/27  Aaa  5,000,000  5,283,150 
Sayre, Hlth. Care Fac. Auth. Rev. Bonds (Guthrie Hlth.), Ser. A, 5 7/8s, 12/1/31  A-  1,000,000  1,072,390 

Puerto Rico (2.4%)       
Cmnwlth. of PR, Hwy. & Trans. Auth. Rev. Bonds, Ser. B, 6s, 7/1/39 (Prerefunded)  BBB+  5,000,000  5,547,100 

South Carolina (2.8%)       
Florence Cnty., Hosp. Rev. Bonds (McLeod Regl. Med. Ctr.), Ser. A, FSA, 5 1/4s, 11/1/23 (Prerefunded)  Aaa  2,515,000  2,727,744 
SC Hosp. Auth. Rev. Bonds (Med. U.), Ser. A, 6 1/2s, 8/15/32 (Prerefunded)  AAA  1,000,000  1,155,620 
SC Jobs Econ. Dev. Auth. Hosp. Fac. Rev. Bonds (Palmetto Hlth. Alliance), Ser. A, 7 3/8s, 12/15/21 (Prerefunded)  BBB+/F  600,000  705,300 
SC Tobacco Settlement Rev. Mgt. Rev. Bonds, Ser. B, 6 3/8s, 5/15/28  BBB  1,750,000  1,875,685 

South Dakota (0.9%)       
SD Edl. Enhancement Funding Corp. Rev. Bonds, Ser. B, 6 1/2s, 6/1/32  BBB  2,000,000  2,178,200 

Tennessee (4.3%)       
Johnson City, Hlth. & Edl. Fac. Board Hosp. Rev. Bonds       
(Mountain States Hlth.), Ser. A, 7 1/2s, 7/1/25  BBB+  2,000,000  2,347,140 
(First Mtge. -Mountain States Hlth.), Ser. A, MBIA, 6s, 7/1/21  Aaa  7,000,000  7,624,400 

Texas (9.4%)       
Alliance, Arpt. Auth. Rev. Bonds (Federal Express Corp.), 6 3/8s, 4/1/21  Baa2  2,500,000  2,555,850 
Columbus, Indpt. School Dist. G.O. Bonds, PSFG, 5 1/8s, 8/15/29  Aaa  4,525,000  4,803,514 
Conroe, Indpt. School Dist. G.O. Bonds (School House), PSFG, 5s, 2/15/26  Aaa  2,905,000  3,058,616 
Gateway, Pub. Fac. Corp. Rev. Bonds (Stonegate Villas Apt.), FNMA Coll., 4.55s, 7/1/34 (Prerefunded)  Aaa  750,000  772,500 
Harris Cnty., Hlth. Fac. Rev. Bonds (Memorial Hermann Hlth. Care), Ser. A, 6 3/8s, 6/1/29 (Prerefunded)  A2  1,500,000  1,707,345 
Montgomery Cnty., G.O. Bonds (Library), Ser. B, AMBAC, 5s, 3/1/26  Aaa  1,335,000  1,398,319 
Sam Rayburn Muni. Pwr. Agcy. Rev. Bonds, 6s, 10/1/21  Baa2  1,500,000  1,604,805 
Snyder, Indpt. School Dist. G.O. Bonds (School Bldg.), AMBAC       
5 1/4s, 2/15/24 (Prerefunded)  AAA  1,215,000  1,317,825 
5 1/4s, 2/15/23  AAA  1,150,000  1,250,016 
Socorro, Indpt. School Dist. G.O. Bonds, PSFG, 5s, 8/15/29  AAA  1,360,000  1,426,817 
Tomball, Hosp. Auth. Rev. Bonds (Tomball Regl. Hosp.), 6s, 7/1/19 (Prerefunded)  Baa3  1,700,000  1,803,360 

Utah (6.5%)       
Tooele Cnty., Harbor & Term. Dist. Port Fac. Rev. Bonds (Union Pacific), Ser. A, 5.7s, 11/1/26  Baa2  500,000  524,290 
UT Cnty., Env. Impt. Rev. Bonds (Marathon Oil), 5.05s, 11/1/17  Baa1  675,000  708,467 
UT State Pwr. Supply Rev. Bonds (Intermountain Pwr. Agcy.), Ser. A       
MBIA, 6.15s, 7/1/14  Aaa  4,720,000  4,854,237 
MBIA, U.S. Govt. Coll., 6.15s, 7/1/14 (Prerefunded)  Aaa  8,280,000  8,773,902 

Vermont (0.4%)       

VT Hsg. Fin. Agcy. Rev. Bonds, Ser. 19A, FSA, 4.62s, 5/1/29  Aaa  975,000  988,475 

Virginia (0.9%)       
Prince William Cnty., Indl. Dev. Auth. Hosp. Rev. Bonds (Potomac Hosp. Corp.), 5.35s, 10/1/36  A3  2,000,000  2,105,560 

Washington (1.1%)       
Tobacco Settlement Auth. of WA Rev. Bonds, 6 1/2s, 6/1/26  BBB  2,355,000  2,576,229 

West Virginia (6.2%)       
Econ. Dev. Auth. Lease Rev. Bonds (Correctional Juvenile Safety), Ser. A, MBIA, 5s, 6/1/29  Aaa  7,500,000  7,897,950 
West Virginia U. Rev. Bonds (Impt. West VA. U.), Ser. C, FGIC, 5s, 10/1/26  Aaa  6,000,000  6,338,100 

Wisconsin (3.6%)       
Badger Tobacco Settlement Asset Securitization Corp. Rev. Bonds       
7s, 6/1/28  BBB  1,800,000  1,986,804 
6 3/8s, 6/1/32  BBB  3,500,000  3,747,310 
WI State Hlth. & Edl. Fac. Auth. Rev. Bonds (Wheaton Franciscan), 5 3/4s, 8/15/30  A2  2,500,000  2,665,825 

Wyoming (0.4%)       
Sweetwater Cnty., Poll. Control VRDN (Pacificorp.), Ser. B, 3.05s, 1/1/14  VMIG1  850,000  850,000 

Total investments (cost $347,746,623) (b)      $365,265,268 

FUTURES CONTRACTS OUTSTANDING at 2/28/06 (Unaudited)         
  Number of    Expiration  Unrealized 
  contracts  Value   date  depreciation 

U.S. Treasury Note 10 yr (Long)  43  $4,639,969  Jun-06  $(5,168) 


(a) Percentages indicated are based on net assets of $230,148,837.

(RAT) The Moody's, Standard & Poor's or Fitch's ratings indicated are believed to be the most recent ratings available at February 28, 2006 for the securities listed. Ratings are generally ascribed to securities at the time of issuance. While the agencies may from time to time revise such ratings, they undertake no obligation to do so, and the ratings do not necessarily represent what the agencies would ascribe to these securities at Feburary 28, 2006. Securities rated by Putnam are indicated by "/P". Securities rated by Fitch are indicated by "/F". Security ratings are defined in the Statement of Additional Information.

(b) The aggregate identified cost on a tax basis is $347,746,623, resulting in gross unrealized appreciation and depreciation of $18,230,850 and $712,205, respectively, or net unrealized appreciation of $17,518,645.

(SEG) A portion of this security was pledged and segregated with the custodian to cover margin requirements for futures contracts at February 28, 2006.

At February 28, 2006, liquid assets totaling $4,639,969 have been designated as collateral for open futures contracts.

144A after the name of a security represents those exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers.

The rates shown on VRDN and Mandatory Put Bonds are the current interest rates at February 28, 2006.

The dates shown on Mandatory Put Bonds are the next mandatory put dates.

The fund had the following industry group concentrations greater than 10% at February 28, 2006 (as a percentage of net assets):   
Health care  34.5% 
Utilities and power  26.1 
Transportation  14.4 
The fund had the following insurance concentrations greater than 10% at February 28, 2006 (as a percentage of net assets):   
MBIA  28.9% 
AMBAC  20.8 
FGIC  15.2 

Security valuation Tax-exempt bonds and notes are valued at fair value on the basis of valuations provided by an independent pricing service, approved by the Trustees. Such services use information with respect to transactions in bonds, quotations from bond dealers, market transactions in comparable securities and various relationships between securities in determining value. Other investments are valued at fair value following procedures approved by the Trustees. Such valuations and procedures are reviewed periodically by the Trustees.

Futures and options contracts The fund may use futures and options contracts to hedge against changes in the values of securities the fund owns or expects to purchase, or for other investment purposes. The fund may also write options on swaps or securities it owns or in which it may invest to increase its current returns.

The potential risk to the fund is that the change in value of futures and options contracts may not correspond to the change in value of the hedged instruments. In addition, losses may arise from changes in the value of the underlying instruments, if there is an illiquid secondary market for the contracts, or if the counterparty to the contract is unable to perform. Risks may exceed amounts recognized on the statement of assets and liabilities. When the contract is closed, the fund records a realized gain or loss equal to the difference between the value of the contract at the time it was opened and the value at the time it was closed. Realized gains and losses on purchased options are included in realized gains and losses on investment securities. If a written call option is exercised, the premium originally received is recorded as an addition to sales proceeds. If a written put option is exercised, the premium originally received is recorded as a reduction to cost of investments.

Futures contracts are valued at the quoted daily settlement prices established by the exchange on which they trade. The fund and the broker agree to exchange an amount of cash equal to the daily fluctuation in the value of the futures contract. Such receipts or payments are known as “variation margin.” Exchange traded options are valued at the last sale price, or if no sales are reported, the last bid price for purchased options and the last ask price for written options. Options traded over-the-counter are valued using prices supplied by dealers. Futures and written option contracts outstanding at period end, if any, are listed after the fund’s portfolio.

For additional information regarding the fund please see the fund's most recent annual or semiannual shareholder report filed on the Securities and Exchange Commission's Web site, www.sec.gov, or visit Putnam's Individual Investor Web site at www.putnaminvestments.com

Item 2. Controls and Procedures:

(a) The registrant's principal executive officer and principal financial officer have concluded, based on their evaluation of the effectiveness of the design and operation of the registrant's disclosure controls and procedures as of a date within 90 days of the filing date of this report, that the design and operation of such procedures are generally effective to provide reasonable assurance that information required to be disclosed by the registrant in this report is recorded, processed, summarized and reported within the time periods specified in the Commission's rules and forms.

(b) Changes in internal control over financial reporting: Not applicable

Item 3. Exhibits:

Separate certifications for the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Investment Company Act of 1940, as amended, are filed herewith.


Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Putnam Investment Grade Municipal Trust

By (Signature and Title):

/s/ Michael T. Healy
Michael T. Healy
Principal Accounting Officer
Date: April 28, 2006

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title):

/s/ Charles E. Porter
Charles E. Porter
Principal Executive Officer
Date: April 28, 2006

By (Signature and Title):

/s/ Steven D. Krichmar
Steven D. Krichmar
Principal Financial Officer
Date: April 28, 2006